The present invention relates to an apparatus for continuous electrolytic descaling of a steel wire with mill scales and, more particularly, to an apparatus for continuously removing mill scales formed on the surface of a steel wire by an electrolytic pickling by induced current flow method (the term "induced current flow" used herein is to be understood to mean that current flows through a wire without any contact with an electric power source) using a plurality of electrodes, prior to the stretching process in, for example, an apparatus for continuous stretching.
Steel wires (hereinafter referred to as "wire" or "wires") produced in wire plants usually have mill scales formed thereon. These scales are now removed either by a chemical or by a mechanical method. Classified into the chemical descaling methods are pickling, electrolytic pickling and salt bath methods which classified into the mechanical descaling methods are rolling and hot blasting methods. The chemical descaling method (particularly pickling method) usually comprises the steps of pickling, rinsing, coating, and drying. A wire thus descaled is advanced to a stretching process as a secondary process. Each of these steps involves transporation of wires which causes considerable losses in time and labor. Accordingly, various considerations have been made for rationalization of such equipment, particularly for rationalization of the descaling step. In fact, there has been proposed a continuous descaling process by, for example, shot blasting or electrolytic pickling. However, the shot blasting has a disadvantage in that it produces poor adhesion of a lubricant and the electrolytic pickling also has a disadvantage in that its application is limited to rationalization of the descaling step and it is not applicable for the purpose of continuous operation of the entire stretching equipment. Several different types of electrolytic descaling apparatuses adaptable for automation of the entire stretching step have been proposed. However, since most of them adopt a direct current flow method, they have a common disadvantage that lead wires from an electric power source must be brought into direct contact with a wire being processed and cause sparks on the surfaces of the scales of the wire being continuously electrolytically descaled, thereby causing disconnections of the lead wires. The term "direct current flow" used herein is to be understood to mean a system in which electrodes and the wire are connected directly to the electric power source. On the other hand, the term "indirect or induced current flow" used herein is to be understood to mean a system in which a wire (not connected to the electric power source) is disposed with a pair or a plurality of pairs of electrodes which are connected to a direct current power source and the electric current is made to flow through an electrolytic solution.